Record breakers of the bird world

Bird ringing has come a long way since it's inception in 1909. It was primarily set up to answer some basic questions, like where do our birds go and how long do they live. Since then, an amazing amount of information has been gathered that answers many more complex questions, like why a certain species population changes each year and where in Britain or Ireland are they declining. More information can be found on the BirdTrends and ringing surveys pages.

 

At this time of year, all of the previous year's data have been loaded and checked and the Ringing and Nest Recording Team pull together some of this information to produce the Online Ringing & Nest Recording Report. The report includes annual totals for ringing and nest recording, as well as information on recoveries, but it also covers one basic question... how long can a bird live?

The longevity records for 2016 have now been updated and there are some interesting new records. Relatively new colonists like the Little Egret often feature. As they have only been ringed in any numbers in Britain and Ireland in the last fifteen years, we probably haven't yet established the normal maximum life expectancy; the record currently stands at 10 years and five months.

Little Egret chicks. Photo by Graham Giddens

Last year saw 17 records broken including three owl species; Barn Owl, Little Owl and Tawny Owl with ages reaching 15 years, 13 years and 23 years respectively. Some finches also did well with Twite, Lesser Redpoll reaching six years and Goldfinch reaching 10 years.

Lots of these record breakers were caught by a ringer, as opposed to being found dead or being identified by colour marks. Where ringers monitor the same populations annually, the potential for individuals to be caught again increases. This is exactly what happened with three of the record breakers, Little Ringed Plover, Peregrine and Nuthatch, which broke their own records after being re-encountered in 2016! 

The Puffin longevity record was broken again in 2016, and the oldest-known bird in Britain or Ireland is now a ripe old age of 37 years. The individual that broke the record, seen in the photo below, was ringed and re-encountered by the Shiants Auk Ringing Group, who ring in the Western Isles. The previous record holder was also a bird from the Shiants.

The oldest-known BTO-ringed Puffin, by Liz Scott.

We won't be analysing the 2017 records until next year but we already know that the current longevity record for Jackdaw has been broken. Originally ringed in April 1999 by Declan Manley, and subsequently re-caught in 2005, 2007, 2012 and now in 2017. A Goldfinch ringed in Nottinghamshire and found dead in Devon has also broken the 2016 longevity, adding another couple of months on to the current record.

Longevity records are the maximum a species has been recorded to live but most birds do not manage to reach this age. The average life expectancy and lots of other interesting facts can be found on our BirdFacts page.

RAS: Renewing Acquaintances in Spring

For almost 20 years, the Retrapping Adults for Survival (RAS) scheme has used standardised bird ringing as a tool to monitor adult survival rates of species not frequently caught at Constant Effort Sites. The results are used to generate annual survival estimates which help us to understand more about the contribution changes in the probability of mortality make to population trends recorded by surveys such as the BTO/JNCC/RSPB Breeding Bird Survey (BBS). Birds are generally faithful to breeding sites between years, so RAS methodology aims to re-encounter as high a proportion of returning adults as possible each year; for some species, this task can be made significantly easier by fitting colour-marks, allowing birds to be individually identified without capture. 

The initial uptake for RAS was fantastic, with 75 datasets received in 1998. Since then, the number of projects has risen steadily and in 2015, a tremendous 190 datasets were received. We now have over 200 active projects studying 59 different species. 60% of projects focus on one of the 24 target species, as outlined in the Demographic Targeting Strategy, with a further 11% of projects targeting seabirds (which don’t yet feature in the target species list).

The most frequently studied species are still House Sparrow and Pied Flycatcher, which are the focus of 23 projects each. In third place is Sand Martin, which is studied by 15 RAS ringers, often at artificial banks such as the one at Rutland Water which enable breeding success to be monitored concurrently. Following closely behind is Starling (14 projects), a species that has become increasingly popular in recent years. Prior to 2013, there were only two RAS projects on this red-listed species so the additional data now being produced are very welcome! Not quite making double figures are Dipper and Reed Warbler, which are the species of choice for nine RAS ringers each. Perhaps surprisingly, there are still fewer RAS projects than we might expect on some generally well-ringed species, such as Swallow and Tree Sparrow (six projects each) – we would love to hear from anyone interested in taking up the challenge of a RAS on these species.

This colour-ringed Starling is part of a RAS population in Lancashire. Photo by Peter Alker.

The fruits of RAS ringers’ labours have just been published. The full suite of national RAS results for 2015 is now available and includes a trend for Tawny Owl, which we have been able to produce for the first time following the submission of some valuable historical data. RAS works particularly well for longer-lived species, such as owls and seabirds. A number of ringers with existing, long-term ringing projects have recently registered for RAS, instantly enabling us to produce survival trends for their studies.

A trend for Tawny Owl is available for the first time. Photo by Ruth Walker.

 

RAS survival trends for 12 species (Little Owl, Jackdaw, Sand Martin, Swallow, House Martin, Dipper, Pied Flycatcher, Stonechat, Wheatear, House Sparrow, Linnet and Siskin) are also included in the annually produced BirdTrends report, which provides a range of information about population trends and their potential drivers for over 100 breeding bird species.

We are very grateful to all our fabulous RAS ringers who put so much time and effort into generating this incredibly valuable data. Anybody considering starting a RAS or wondering whether a current project could be suitable for RAS is encouraged to contact the RAS organiser.

2015 nesting season underway by New Year!

Dave Leech writes:

For many BTO nest recorders, particularly those monitoring Barn Owl repeat breeding attempts well into the late autumn, it feels like the 2014 breeding season has only just drawn to a close. However, the respite is brief – while we seek shelter from the biting winter gales, the avian community is gearing up for the coming spring.

The Met Office have recently announced that 2014 was the warmest year on record in the UK and this winter has certainly been mild if, as most bird ringers will point out, a tad windy. Mild weather at the start of the year can certainly stimulate opportunistic singing, and I’ve already heard Great Tit, Wren and Dunnock in song within walking distance of my house in southwest Norfolk; nest recorder Mark Lawrence has been listening to the reedy warbling of the latter since early December on his patch in Devon.

Dunnock singing - Liz Cutting

While the nestling diet of these birds is not necessarily conducive to early breeding, species able to take advantage of soil invertebrates are less limited by food availability and may breed opportunistically at the end of winter, particularly around human habitation where temperatures are artificially raised and bird feeders provide additional sustenance. Nest recorder Mark Lucas has already reported his first clutch of Robin eggs in North Yorkshire via Twitter, found on the 9th January, beating the earliest record submitted to the BTO Nest Record Scheme by a fortnight. A pair of Mistle Thrush breeding in a Glasgow park were also flagged up on Twitter, the young having fledged in the last week.

Mistle Thrush nest - Herbert and Howells

Some birds couldn’t even wait for the New Year to start the 2015 season. RSPB warden Doug Radford was told of a Moorhen on eggs in Cambridgeshire in mid-December which had hatched by Christmas, and we’ve also received reports of Grey Heron laying at the start of the month. Not to be outdone, the BTO’s own Nick Moran stumbled across a brood of small Mallard ducklings on the 12th December at our reserve in Norfolk.

Mallard with ducklings - John Harding

While these examples demonstrate birds ability to respond to windows of opportunity, they are all anomalies. The data collected by BTO volunteers for the Nest Record Scheme over the past 75 years tells us that the main Robin breeding season kicks off towards the end of March, while most Moorhens start to lay from the beginning of April onwards.  Grey Herons are early breeders (Table 1), but laying doesn’t typically start until mid-February, with Raven generally the next species to follow in any number, then Tawny Owl, Collared Dove and Magpie at the very beginning of March.

BTO data have played a key role in demonstrating the advance in avian laying dates in response to the warming climate, as summarised in the recent BirdTrends report, and it is vital to ensure that this monitoring is ongoing. So, if you’re looking for a New Year’s resolution that furthers your knowledge while also giving something back to the conservation effort, why not make 2015 your first year as a nest recorder?

Table 1. Top 10 earliest UK breeders as calculated using Nest Record Scheme data for the period 2000-2009. Dates shown are the fifth percentile of the laying date distribution. Note that some early breeding species (e.g. Long-eared Owl, Crossbill) are excluded due to very small sample sizes.